This invention relates to devices for medical treatment of morbid obesity in humans.
Morbid obesity is a chronic medical illness defined as overweight of 50 to 100 percent or 100 pounds above the ideal body weight.
Characteristic features of this illness include predominantly genetic origin, onset of disease in youth, a generally relentless progression throughout life, and a long-term cure rate of less than 5 percent. Morbid obesity has many serious health ramifications. A strong association exists between obesity and hypertension, hyperlipidemia and exacerbation of diabetes mellitus. These conditions, in turn, increase the risk factors for coronary artery disease (heart attack) and cardiovascular disease (stroke), which are leading causes of premature mortality and morbidity. Obesity also produces mechanical and physical stresses that aggravate or cause sciatica and joint problems, especially arthritis of the hips and knees. Another serious disease limited to obese individuals is a Pickwickian syndrome. This syndrome is characterized by nighttime episodes of upper airway obstruction which cause hypoxemia and, if left untreated, lead to pulmonary hypertension and heart failure. Weight loss will reverse this disease completely if instituted before permanent cardiac damage develops. Multiple other medical problems are more common in obese individuals such as gallstones, varicose veins, thromboembolism and hernias. In addition, morbid obesity can lead to psychosocial difficulties such as depression, loss of self-esteem and decreased employability.
To date, numerous attempts have been made to cause weight loss in morbidly obese patients. None of them have been entirely successful. The weight loss methods can be broadly divided into behavior modification and medical diets, surgical procedures, and devices.
Medical dietary regimes and behavior modification are used as a first line of treatment of obesity since they have almost no side effects or complications, when properly applied and monitored. However, these methods are usually unsuccessful in the treatment of morbid obesity because they depend solely upon the willpower of the patients. Only after these methods of treatment fail and the health risks of staying morbidly obese are judged to be serious, should interventional methods, including devices and surgical procedures, be employed. Behavior modification and medical diets, nevertheless, remain useful and necessary adjuncts to treatment by devices or surgery.
Surgical procedures for treatment of obesity include procedures that lead to weight loss by malabsorption such as jejunoileal or gastric bypass surgery, gastroplasty and gastric stapling and oral surgical procedures such as wiring shut the patient's jaws to reduce food intake. These procedures are usually quite effective in producing weight loss but some of them have been accompanied by serious complications and side effects, including operative mortality as high as three to six percent, postoperative wound infection, liver disfunction and failure, kidney stones, diarrhea and the need for further surgeries to treat intestinal obstruction or hernias, or to revise original surgery because of intolerable side effects.
Many weight loss devices are based on placing within the lumen of the stomach a bag or a balloon filled with air or liquid, which controls the patient's desire to eat by distension of the stomach. Theoretically, the distension of gastric by objects such as balloons as well as by food stimulates the neuroreceptors located in the sub-mucosa of the upper fundus of the stomach, and these receptors send signals to the brain causing the patient to experience the sensation of satiety.
To date, two main approaches have been suggested to introduce inflatable balloon-like devices into the abdomen of obese patients. The first approach, suggested by Berson (U.S. Pat. No. 4,246,893), was surgical placement of the balloon-like device through an incision in the abdominal wall and the peritoneum into the upper abdomen adjacent and anterior to the stomach. The balloon is intended to exert pressure on the stomach from outside.
The second approach is placing the distensible device within the lumen of the stomach. This approach was described in the patent of Berman (U.S. Pat. No. 4,133,315), wherein an inflatable bag with a flexible tube is positioned in the stomach either non-surgically (i.e., through the mouth, down the esophagus and into the stomach), or surgically by creating a direct incision in the abdominal wall and performing a gastrostomy, with the filling tube surgically placed through the abdominal wall.
The surgical placement of the intragastric bag by performing a gastrostomy, as described by Berman, can be accompanied by serious complications and side effects associated with any surgical procedure and presents complications when the balloon needs to be replaced. In the case of having a filling tube permanently extended up through the esophagus and out of the nasal cavity or out of the mouth, as again described by Berman, is a major inconvenience for the patient. On the other hand, it is beneficial for the patient to fill and empty the intragastric balloon periodically. The emptying of the balloon provides periods of relief and feelings of well being for the patient.
The need for improvements over these approaches has been recognized for a number of years. Several proposals (Foster, Jr., U.S. Pat. No. 4,485,805; Lai et al., U.S. Pat. No. 4,739,758; Kullas et al., U.S. Pat. No. 4,723,547) use a free-floating balloon in the patient's stomach without having the filling tube attached. Since they recognized the importance of inflating and deflating the balloon and the above-discussed disadvantages of having a permanently attached filling tube, they constructed detachable means for filling or emptying the balloon introduced through the esophagus.
Similarly, Gan et al. (U.S. Pat. No. 5,084,061) recently proposed a free-floating inflatable intragastric balloon with a self-sealing valve, wherein the balloon is inflated or deflated using an endoscope introduced through the esophagus down to the stomach.
However, these proposals still have not allowed a frequent filling and emptying of the balloon on an hourly or daily basis since they require introduction of an endoscope through the esophagus, which is a procedure conducted by a physician on a sedated patient.
In summary, there continues to be a need for an intragastric device which can be nonsurgically placed in the lumen of the stomach and frequently filled and emptied, and in particular an intragastric device that is also easily withdrawn from the lumen of the stomach, inspected, replaced if needed, and reinserted into the lumen of the stomach. Preferably, all these steps should be done without any sedation or any major discomfort to the patient.